we learned today that asiana airlines flight 214 was flying far too slowly in the seconds before it crashed while attempting to land in san francisco. today, as investigators continued to check every square inch of the wreckage, they told us the landing speed of the boeing 777 was nearly 23% below what is typical for that type of aircraft. what they are still trying to answer tonight is why. one area of focus is the pilot who was flying the plane when it crashed. it was the first time he attempted to land a 777 at the san francisco airport. we have a series of reports tonight and we will begin with john blackstone in san francisco. john? >> reporter: scott, the four pilots who were aboard this plane are being interviewed today by investigators for the national transportation safety board. now, until those interviews are complete, n.t.s.b. officials are saying little about the pilot's role in this crash. investigators revealed today they found debris from the plane's tail section in the water beyond the edge of the runway, evidence impact occurred well before the runway began. n.t.s.b. chair